Independent Beacon Based Light Position System

1. A method of determining a position of a mobile device when the mobile device is indoors by using asynchronous light sources that each autonomously, and without communication to or from a server, broadcast an identifier as a modulated broadband light signal, the method comprising: capturing, with an image sensor of the mobile device, an image comprising a modulated broadband light signal from one of the asynchronous light sources; analyzing the captured image, using the mobile device, to demodulate the modulated broadband light signal from the one asynchronous light source and to determine an identifier specific to the one asynchronous light source; and transmitting the identifier determined from the captured image over a wireless communication link from the mobile device to the server, without communication to any light source, to obtain the position of the mobile device without using identifiers from the other asynchronous light sources, wherein the identifier corresponds to a pattern of distortions within the captured image, the pattern of distortions being related to a modulation frequency of the modulated broadband light signal from the one asynchronous light source.

2. The method of claim 1 , wherein the broadband light signal from the one asynchronous light source is modulated at a frequency ranging from 60 hertz to 5000 hertz.

3. The method of claim 1 , further comprising receiving location information from a second source at the mobile device, the location information not encoded within visible light.

4. The method of claim 3 , wherein the second source comprises at least one of GPS, accelerometer, Bluetooth, Wifi, or cellular tower identification information.

5. The method of claim 3 , further comprising, before or after obtaining the position of the mobile device, (i) disposing the mobile device in a different location in which the mobile device cannot determine an identifier associated with a corresponding light source, and (ii) utilizing the location information to obtain an approximate position of the mobile device.

6. The method of claim 1 , wherein the identifier specific to the one asynchronous light source includes location information identifying geo-location of the one asynchronous light source as well as a randomly generated identification number.

7. The method of claim 1 , further comprising communicating to the server the identifier specific to the one asynchronous light source and location information regarding location of the mobile device, wherein the location information is sent to the server to constrain a search space for the identifier specific to the one asynchronous light source.

8. The method of claim 1 , further comprising triggering capture of the image on the mobile device based on a change of conditions on the mobile device.

9. The method of claim 8 , wherein the change of conditions comprises a change in an amount of ambient light detected at the mobile device.

10. The method of claim 1 , wherein the image sensor captures different portions of the image at different times, thereby forming the pattern of distortions on the image.

11. The method of claim 1 , wherein the pattern of distortions comprises alternating dark and light stripes.

12. The method of claim 11 , wherein analyzing the captured image comprises measuring stripe width within the captured image.

13. The method of claim 11 , wherein widths of stripes in the captured image are inversely related to a modulation frequency of the modulated broadband light signal from the one asynchronous light source.

14. The method of claim 1 , wherein the image sensor comprises a CCD image sensor.

15. The method of claim 1 , wherein the image sensor comprises a CMOS image sensor.

16. The method of claim 1 , wherein the image sensor comprises a rolling shutter for exposing different portions of the image sensor at different times.

17. A mobile device configured to determine the position of the mobile device when indoors by using asynchronous light sources that each autonomously, and without communication to or from a server, broadcast an identifier as a modulated broadband light signal, the mobile device comprising: an image sensor configured to capture images, each image comprising modulated broadband light signals; a processor configured to run a module configured to analyze the captured images by demodulating modulated broadband light signals to determine identifiers specific to light sources corresponding thereto; and a wireless interface that is configured to (i) communicate over a wireless medium, from the mobile device to the server, and without communication to any light source, the identifiers determined by the processor, and (ii) receive from the server the position of the mobile device determined from the determined identifiers without using identifiers from other light sources, wherein each of the determined identifiers corresponds to a pattern of distortions within an image captured with the image sensor, each pattern of distortions being related to a modulation frequency of the modulated broadband light signal broadcast by a corresponding light source.

18. The mobile device of claim 17 , wherein each broadband light signal is modulated at a frequency ranging from 60 hertz to 5000 hertz.

19. The mobile device of claim 17 , wherein the processor is configured to receive location information from a second source at the mobile device, the location information not encoded within visible light.

20. The mobile device of claim 19 , wherein the second source comprises at least one of GPS, accelerometer, Bluetooth, Wifi, or cellular tower identification information.

21. The mobile device of claim 17 , wherein the light source identifier includes location information identifying geo-location of the light source as well as a randomly generated identification number.

22. The mobile device of claim 17 , wherein the wireless interface is configured to communicate to the server the light source identifier and location information regarding location of the mobile device, wherein the location information is sent to the server to constrain a search space for the light source identifiers.

23. The mobile device of claim 17 , wherein the processor is configured to trigger capture of the image on the mobile device based on a change of conditions on the mobile device.

24. The mobile device of claim 23 , wherein the change of conditions comprises a change in an amount of ambient light detected at the mobile device.

25. The mobile device of claim 17 , wherein the image sensor is configured to capture different portions of each image at different times, thereby forming each pattern of distortions.

26. The mobile device of claim 17 , wherein each pattern of distortions comprises alternating dark and light stripes.

27. The mobile device of claim 26 , wherein analyzing captured images comprises measuring stripe width therewithin.

28. The mobile device of claim 26 , wherein widths of stripes are inversely related to a modulation frequency of a modulated broadband light signal.

29. The mobile device of claim 17 , wherein the image sensor comprises a CCD image sensor.

30. The mobile device of claim 17 , wherein the image sensor comprises a CMOS image sensor.

31. The mobile device of claim 17 , wherein the image sensor comprises a rolling shutter for exposing different portions of the image sensor at different times.